As one of machines for mechanically juicing fruits or vegetables, juicers have been widely used for a long period of time. However, a conventional centrifugal juicer will oxidize enzymes in fruits and vegetables, and the produced juice is unsatisfactory in color and taste, so the conventional centrifugal juicer has been unable to meet people's requirements for the high-quality life. By juicing fruits and vegetables in a slow grinding manner, a slow grinding juicer may completely reserve enzymes and result in juice with natural color and delicate taste. The slow grinding juicer has been developed steadily.
However, slow grinding juicers in the current market have a single structure in terms of filter screens. A conventional filter screen is of a single-layer structure and unable to have both grinding and cutting functions, and a wall cutter on an inner wall and a rotor have a poor cooperative grinding effect and an unreasonable structure. Consequently, fruit or vegetable raw materials, when being processed, are likely to slide to the bottom of the filter screen, the juicing effect will be reduced due to an insufficient grinding force, and the obtained juice basically contains no dietary fiber. Furthermore, the conventional rotor, spiral ribs on the surface of the rotor and the wall cutter on the inner wall of the filter screen are made of plastics, and are easy to wear after long-term use, so that the grinding effect will be reduced and it is disadvantageous for food safety.
In addition, the on/off of the conventional juicer is controlled by a single control button, and the control button is provided on a side face of a machine base, which is easy to touch. Thus, when the switch is touched by accident, particularly by children, the rotor starts rotating without consciousness, so that it is very likely to cause accidents. In addition, in order to increase the capacity and use convenience of juicers, at present, majority of juicers are designed as a large-aperture structure, and the large-aperture juicers are sufficient to accommodate an adult's hand. However, since the height of an upper cover of a large-aperture juicer is insufficient, when the machine is rotating, there are safety risks if a person has his/her hands into this juicer.